The invention relates generally to the field of oral care, and in particular to toothbrushes.
Tooth brushing and flossing are fundamental steps in achieving good oral hygiene. The practice of flossing, unfortunately, has not met with widespread acceptance among the general populace even though it is acknowledged by the general populace that flossing is something that should be completed as part of good oral hygiene. Furthermore, even people who floss oftentimes do not perform adequate flossing in hard to reach areas of the mouth. Unfortunately, while most commercially available toothbrushes clean the outer buccal face of teeth adequately, they fail to provide improved cleaning of plaque and debris from the gingival margin, interproximal areas, lingual surfaces and other hard to reach areas of the mouth.
One reason that such toothbrushes do not adequately clean the interproximal region is that the tufts are not angled in a direction to optimize interproximal and subgingival penetration. As such, these tufts cannot extend far enough into the interproximal region. Another reason for poor interproximal penetration/cleaning is that the bristle/tuft density is too high: having a large number of bristles/tufts provides good surface cleaning but hinders the bristles from penetrating between teeth.
Some brushes have tufts of bristles which have angled tufts which either appear to cross when viewed head-on (see for example U.S. Pat. No. 4,706,322 (the ""322 patent), incorporated herein by reference) or from the side (see for example U.S. Pat. No. 3,085,273 (the ""273 patent), incorporated herein by reference) to provide better interproximal penetration. The crossing tufts of the ""322 patent will more effectively penetrate between teeth when the brush is being moved up and down rather than back and forth. Likewise, the crossing tufts of the ""273 patent will more effectively penetrate between teeth when the brush is being moved back and forth rather than up and down.
Some current toothbrush designs involve filament tufts angled away from the center line/long axis of the brush head (FIG. 7) and some current toothbrush designs involve tuft filaments angled along the center line of the brush (FIG. 8). When these toothbrushes are placed on or against the teeth, the filaments bend and are deflected away from the gumline area.
U.S. Pat. No. 4,570,282 discloses a toothbrush having bristle elements arranged in two banks. The free ends of the bristle elements in the first bank extend convergingly with the free ends of the bristle elements in the second bank to provide a V-shaped tooth receiving channel having an acute included angle of from about 10 to 55 degrees. The bristle elements in the banks which are closest together extend into contact with one another at the bristle tips to define a doublet of mutually supported bristle elements.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a toothbrush includes a head having bristle tufts implanted therein. At least two of the tufts cross so as to permit at least some the bristles to intermingle. One of the two tufts is located adjacent a long side of the head.
Another aspect of the present invention relates to a toothbrush comprising a head having at least 2 bristle tufts which have a compound crossing angle such that one of the tufts eclipses at least a portion of the bristles of the other tuft when (a) viewed from a side of the toothbrush, and (b) viewed from an end of the toothbrush.
Such a compound crossing angle allows the tufts to more effectively penetrate in between teeth both when the brush is being moved up and down, and, back and forth.
Another aspect of the present invention relates to a toothbrush having a head with at least 2 bristle tufts. The head has two portions which define an opening in an interior portion of the head such that water can flow through this opening.
Allowing water to flow through an opening in a central portion of the head facilitates removal of excess toothpaste and other debris, thus enhancing the cleanliness of the brush over time.
A still further aspect of the invention relates to a toothbrush having a head with bristle tufts implanted therein. At least two of the tufts cross so as to permit at least some of the bristles to intermingle. At least some of the intermingled bristles from one of the two tufts extends past the other tuft.
According to another aspect of the invention, a toothbrush includes a handle, a head extending from the handle and having a top surface, and a plurality of tufts of bristles projecting from the top surface of the head. The cumulative cross-sectional area of each of the bristles defining a first area. A plane intersects all of the bristles except the shortest bristle and is tangent to or intersects at least a portion the free end of the shortest bristle. A perimeter located in the plane connects an outer surface of all outer tufts, the area within the perimeter defining a second area. The ratio of the first area to the second area is between about 5% to about 20%.
The previous paragraph describes a brush having a relatively low density of bristles/tufts. The density needs to be high enough so that it will clean the exposed tooth surfaces and be acceptable to consumers, yet low enough so that at least some of the bristles can penetrate and clean between teeth.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.